grammar - How many verb endings to express "do this (please)"?

I'm familiar with the て and てください forms of a verb to give a command/request and request, respectively. However, I've run across these other forms and really don't know which to use in what situation. I'll just list all the ones I've run across.

• 止めて下さい 　　　


• 止めてくれ


• 止めて 　　　


• 止めなさい


• 止めとけ


• 止めろ

I believe the first is the most polite and last is the most rude. The others in the middle are a guess. However, when and where to use these forms are a mystery to me.

Note: I'm focused on the endings not the verb itself. Also, if I've missed any, please feel free to add to my list.

Answer

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  ～てください comes from the appending the verb くださる in imperative form. But because くださる is considered a polite verb (meaning "give to me"), its imperative is not felt as a direct command but a request. It is used when the speaker feels socially lower than the listener. (Asking for someone to do something for you especially if it's not expected of him places you "in debt" to the person, making you feel lower with respect to him)

  
  


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  ～てくれ comes from appending the auxiliary verb くれる in imperative. ～てくれる means "to do for me". ～てくれ would be a command to ask someone to do something for you. It is rather neutral and can be used among peers of relatively equal standing.

  
  



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  ～て comes from elision of the auxiliary verb that commands. As with many cases of elision, it is informal. It can be used among peers of relatively equal standing and has feminine undertones.

  
  


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  ～なさい comes from the imperative form of the verb なさる which means "to do". It can be used when the speaker feels socially higher than the listener. (And the conjugation is 止めなさい or Verb-masu + なさい)

  
  


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  Contributed by Chocolate: ～とけ is a contracted form of ～ておけ (て+お→と). It sounds more colloquial. ～ておけ is the imperative of ～ておく which means to do and leave it as it is.

  
  


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  ～ろ(or よ) is just ろ(or よ) appended to the plain imperative form (止め). It is not particularly polite. It is direct though. Used when the situation does not call for politeness or it's more important to be quick and direct than to be polite.